Certainly the Roslyn C# compiler is highly parallel. All files are parsed in parallel, then all classes are bound (semantically analyzed) in parallel, then the IL serialization phase is sequential.
I wouldn't say that's what most people mean by parallel, but in that case I think you're better off building a layer on top of the compiler for that.
For instance, provided deterministic compilation you could keep a networked cache of compiled libraries that would be delivered as needed.
Trying to be network-parallel at any finer level is probably a waste of time -- network and (de)serialization overhead would eat away all the advantages.
Certainly the Roslyn C# compiler is highly parallel. All files are parsed in parallel, then all classes are bound (semantically analyzed) in parallel, then the IL serialization phase is sequential.